$(document).ready(function() {    
    //select all the a tag with name equal to modal
    $('a[name=modal]').click(function(e) {
        //Cancel the link behavior
        e.preventDefault();
        //Get the A tag
        var id = $(this).attr('href');
    
        //Get the screen height and width
        var maskHeight = $(document).height();
        var maskWidth = $(window).width();
    
        //Set height and width to mask to fill up the whole screen
        $('#mask').css({'width':maskWidth,'height':maskHeight});
        
        //transition effect        
        $('#mask').fadeIn(1000);    
        $('#mask').fadeTo("slow",0.8);    
    
        //Get the window height and width
        var winH = $(window).height();
        var winW = $(window).width();
              
        //Set the popup window to center
        $(id).css('top',  winH/2-$(id).height()/2);
        $(id).css('left', winW/2-$(id).width()/2);
    
        //transition effect
        $(id).fadeIn(2000); 
    
    });
    
    //if close button is clicked
    $('.window .close').click(function (e) {
        //Cancel the link behavior
        e.preventDefault();
        $('#mask, .window').hide();
    });        
    
    //if mask is clicked
    $('#mask').click(function () {
        $(this).hide();
        $('.window').hide();
    });            
    
});